Endocrinology Practice Questions

Q: Which of the following conditions causes hypercalcemia with a normal or low parathyroid hormone (PTH) level?

Sarcoidosis. ### Explanation The key to solving this question lies in understanding the **feedback loop** between serum calcium and Parathyroid Hormone (PTH). In a normal physiological state, hypercalcemia should suppress PTH secretion [2]. **1. Why Sarcoidosis is Correct:** Sarcoidosis is a granulomatous disease. Macrophages within the granulomas contain the enzyme **1-alpha-hydroxylase**, which independently converts 25-hydroxyvitamin D into its active form, **1,25-dihydroxyvitamin D (Calcitriol)**. This leads to increased intestinal calcium absorption [2]. The resulting hypercalcemia appropriately **suppresses the parathyroid glands**, leading to low or low-normal PTH levels (PTH-independent hypercalcemia) [2]. **2. Why the Other Options are Incorrect:** * **A & C (Parathyroid Adenoma/Hyperplasia):** These are causes of **Primary Hyperparathyroidism** [1]. Here, the pathology lies within the parathyroid gland itself, which autonomously secretes high levels of PTH despite elevated serum calcium [1]. * **B (Familial Hypocalciuric Hypercalcemia - FHH):** This is caused by an inactivating mutation in the **Calcium-Sensing Receptor (CaSR)** [1]. The parathyroid glands "perceive" normal calcium levels as low, leading to inappropriately **normal or mildly elevated PTH** levels in the presence of hypercalcemia [2]. **3. High-Yield Clinical Pearls for NEET-PG:** * **PTH-Independent Hypercalcemia (Low PTH):** Think of Malignancy (PTHrP), Sarcoidosis/Tuberculosis (Vitamin D mediated), Multiple Myeloma, and Vitamin D toxicity [2]. * **PTH-Dependent Hypercalcemia (High/Normal PTH):** Think of Primary Hyperparathyroidism and FHH [2]. * **Distinguishing FHH from Primary Hyperparathyroidism:** FHH presents with a **Urinary Calcium/Creatinine Clearance Ratio 0.02 in Primary Hyperparathyroidism. * **Sarcoidosis Triad:** Bilateral hilar lymphadenopathy, hypercalcemia, and elevated ACE (Angiotensin-Converting Enzyme) levels.

Q: A 45-year-old man, a known case of chronic renal failure, develops rugger jersey spine. What is the probable cause?

Secondary hyperparathyroidism. **Explanation:** The **Rugger Jersey Spine** is a classic radiological sign pathognomonic for **Renal Osteodystrophy**, specifically caused by **Secondary Hyperparathyroidism**. **1. Why Secondary Hyperparathyroidism is correct:** In chronic renal failure (CRF), the kidneys fail to excrete phosphate and cannot convert Vitamin D to its active form (1,25-dihydroxyvitamin D). This leads to hyperphosphatemia and hypocalcemia, which chronically stimulate the parathyroid glands [3]. The resulting excess Parathyroid Hormone (PTH) increases osteoclastic activity [1]. Radiologically, this manifests as alternating bands of sclerotic (dense) bone at the superior endplates of the vertebrae and radiolucent (decalcified) bone in the center, mimicking the stripes on a British rugby jersey. **2. Why other options are incorrect:** * **Aluminium intoxication:** Previously common due to aluminium-containing phosphate binders, it typically causes **Adynamic Bone Disease** or osteomalacia [1], not the sclerotic bands seen in rugger jersey spine. * **Osteoporosis:** Characterized by a generalized decrease in bone mass. Radiologically, it shows "codfish vertebrae" or wedge fractures, but not the distinct banded sclerosis [2]. * **Osteomalacia:** Involves defective mineralization of the bone matrix [4]. While it occurs in CRF, its hallmark radiological features are **Looser’s zones** (pseudofractures), not vertebral sclerosis. **Clinical Pearls for NEET-PG:** * **Rugger Jersey Spine:** Secondary Hyperparathyroidism (Renal Osteodystrophy). * **Salt and Pepper Skull:** Another classic sign of Hyperparathyroidism (granular decalcification). * **Brown Tumors:** Osteoclastoma-like lesions found in primary or secondary hyperparathyroidism. * **Ivory Vertebrae:** Differential includes Hodgkin’s Lymphoma, Paget’s disease, and Metastatic Prostatic Carcinoma (distinct from Rugger Jersey as the entire vertebra is dense).

Q: When hypothyroidism is caused by pituitary dysfunction (Central hypothyroidism), what is the expected laboratory profile?

No goiter, reduced TSH, low T3, T4. ### Explanation **1. Understanding the Correct Answer (Option B)** Central hypothyroidism occurs due to pathology in the pituitary gland (secondary) or hypothalamus (tertiary). In this condition, the pituitary fails to secrete adequate **Thyroid Stimulating Hormone (TSH)**. * **Hormonal Profile:** Low TSH leads to a lack of stimulation of the thyroid gland, resulting in **low T3 and T4** levels. (Note: TSH may occasionally be "inappropriately normal" but is functionally bio-inactive). * **Goiter Status:** TSH is a trophic hormone; it stimulates the growth of thyroid follicular cells. In central hypothyroidism, the lack of TSH leads to thyroid atrophy rather than hypertrophy. Therefore, **no goiter** is present. **2. Analysis of Incorrect Options** * **Option A & C:** Elevated TSH is the hallmark of **Primary Hypothyroidism** (e.g., Hashimoto’s thyroiditis). In primary failure, the pituitary attempts to compensate for low T4 by increasing TSH production via negative feedback. * **Option D:** A goiter requires a stimulatory factor (usually high TSH or TSH-receptor antibodies). It is physiologically inconsistent to have both low TSH and a goiter in a hypothyroid state. **3. NEET-PG High-Yield Pearls** * **The "Inappropriate" TSH:** In central hypothyroidism, TSH is usually low or low-normal. If you see low T4 with a "normal" TSH, suspect a pituitary cause. * **Rule Out ACTH Deficiency:** Before starting Levothyroxine in central hypothyroidism, always rule out or treat co-existing **adrenal insufficiency**. Giving T4 first can precipitate an acute adrenal crisis by increasing the metabolic clearance of cortisol. * **Monitoring:** Unlike primary hypothyroidism, you **cannot** use TSH to monitor treatment efficacy in central cases. You must monitor **Free T4** levels to adjust the dosage.

Q: Which of the following is NOT recommended as part of comprehensive medical care for patients with diabetes?

Blood insulin levels annually. **Explanation:** The management of Diabetes Mellitus focuses on glycemic control and the prevention of microvascular and macrovascular complications [2]. **Why Option C is correct:** Measuring **blood insulin levels** (fasting or stimulated) is **not recommended** for routine comprehensive care. In clinical practice, insulin levels are highly variable, expensive, and do not correlate directly with glycemic control or the risk of complications. Diagnosis and management are based on glucose levels (FPG, PPG) and HbA1c [1]. Insulin levels are primarily reserved for research or the differential diagnosis of hypoglycemia (e.g., Insulinoma). **Why the other options are incorrect:** * **HbA1c testing (Option A):** This is the gold standard for monitoring long-term glycemic control [2]. It is recommended at least **twice a year** in stable patients and **quarterly (4 times/year)** in those whose therapy has changed or who are not meeting targets. * **Annual nutrition education (Option B):** Medical Nutrition Therapy (MNT) is a cornerstone of diabetes care. Annual review with a dietitian helps reinforce lifestyle modifications and weight management [3]. * **Annual lipid profile (Option C):** Patients with diabetes are at high risk for atherosclerotic cardiovascular disease (ASCVD) [4]. An annual lipid profile is mandatory to decide on statin therapy and monitor cardiovascular risk. **High-Yield Clinical Pearls for NEET-PG:** * **Microalbuminuria screening:** Should be done annually (starting at diagnosis for Type 2, and 5 years after diagnosis for Type 1). * **Dilated Fundus Exam:** Annual screening for retinopathy is essential. * **BP Target:** Generally **<130/80 mmHg** according to recent ADA guidelines. * **Vaccination:** Patients with diabetes should receive annual **Influenza** vaccines and the **Pneumococcal** vaccine.

Q: Periodic paralysis is seen in the setting of hypokalemia (hypokalemic periodic paralysis). A similar type of paralysis is seen in the setting of which of the following conditions?

Thyrotoxicosis. Explanation: Thyrotoxic Periodic Paralysis (TPP) is a rare but life-threatening complication of hyperthyroidism, most commonly seen in males of Asian descent. The underlying mechanism involves an intracellular shift of potassium rather than a total body deficit. 1. Why Thyrotoxicosis is Correct: Excess thyroid hormones ($T_3$ and $T_4$) increase the activity of the Na+/K+-ATPase pump. This leads to an influx of potassium from the extracellular fluid into the cells, resulting in acute hypokalemia [2]. This hyperpolarizes the muscle membrane, making it unexcitable and leading to flaccid paralysis [1]. Attacks are often triggered by high-carbohydrate meals (insulin also stimulates the Na+/K+ pump) or strenuous exercise [1]. 2. Why Other Options are Incorrect: * Hypothyroidism: Usually associated with muscle stiffness, cramps, and delayed relaxation of deep tendon reflexes (Woltman sign), but not acute periodic paralysis. * Hypoadrenalism (Addison’s Disease): Characterized by hyperkalemia due to aldosterone deficiency, which does not cause this specific clinical picture of hypokalemic periodic paralysis. * Cushing Syndrome: While chronic hypercortisolism can cause mild hypokalemia and proximal muscle wasting (myopathy), it does not typically present with acute, reversible episodes of periodic paralysis. High-Yield Clinical Pearls for NEET-PG: * Demographics: TPP has a strong male predilection (up to 20:1), despite hyperthyroidism being more common in females. * Treatment: The definitive treatment is achieving a euthyroid state (e.g., using Propranolol or antithyroid drugs) [2], [3]. * Caution: During an acute attack, potassium should be replaced cautiously to avoid "rebound hyperkalemia" once the shift reverses. * Diagnosis: Low urinary potassium excretion during an attack helps differentiate TPP from renal potassium loss.

Q: A female presents with swelling in the neck, palpitations, and exophthalmos. Which of the following is the most likely diagnosis?

Graves disease. The clinical triad of **neck swelling (goiter)**, **palpitations (hyperthyroidism)**, and **exophthalmos (thyroid-associated ophthalmopathy)** is pathognomonic for **Graves’ Disease** [1], [3]. This is an autoimmune disorder caused by Thyroid Stimulating Immunoglobulins (TSI) that bind to and activate the TSH receptor, leading to excessive thyroid hormone production [1]. Exophthalmos is a specific extrathyroidal manifestation caused by the inflammation of retro-orbital tissues and fat, mediated by T-cells and fibroblasts [3], [4]. **Why other options are incorrect:** * **Granulomatous thyroiditis (De Quervain’s):** Typically presents with a **painful, tender thyroid** gland following a viral prodrome. While it can cause transient hyperthyroidism, it does not cause exophthalmos [2]. * **Hashimoto thyroiditis:** The most common cause of hypothyroidism. While it may present with a goiter, it typically features symptoms of low metabolism (weight gain, cold intolerance) rather than palpitations and exophthalmos. * **Multinodular goitre (MNG):** Presents as an enlarged, lumpy thyroid. While "Toxic MNG" can cause palpitations (hyperthyroidism), it lacks the autoimmune-mediated infiltrative features like exophthalmos. **High-Yield Clinical Pearls for NEET-PG:** * **Graves’ Triad:** Hyperthyroidism + Diffuse Goiter + Ophthalmopathy (Exophthalmos) [3]. * **Specific Sign:** **Pretibial Myxedema** (Dermopathy) is also highly specific to Graves’ [1]. * **Diagnosis:** Low TSH, High T3/T4, and **diffuse increased uptake** on Radioactive Iodine Uptake (RAIU) scan [2]. * **Antibody:** Anti-TSH receptor antibodies (TRAb/TSI) are the gold standard for confirmation [1].

Q: Carcinoid syndrome is associated with all except?

VMA in urine. **Explanation:** Carcinoid syndrome is caused by the systemic release of vasoactive substances (primarily **Serotonin**) from neuroendocrine tumors [1]. **Why "VMA in urine" is the correct answer:** Vanillylmandelic acid (VMA) is the end-metabolite of catecholamines (Epinephrine and Norepinephrine). Elevated urinary VMA is a diagnostic marker for **Pheochromocytoma**, not carcinoid syndrome. The gold-standard biochemical marker for Carcinoid syndrome is **5-HIAA (5-Hydroxyindoleacetic acid)**, which is the urinary metabolite of Serotonin. **Analysis of other options:** * **Flushing of skin:** This is the most common clinical feature (85% of cases), caused by the release of kinins and histamine [1]. * **Skin lesions like pellagra:** Carcinoid tumors divert up to 60% of the body's dietary **Tryptophan** to produce Serotonin. This leads to a deficiency in Niacin (Vitamin B3) synthesis, resulting in pellagra-like symptoms (Dermatitis, Diarrhea, Dementia) [2]. * **Bronchospasm:** Occurs in about 15% of patients due to the release of histamine and serotonin, manifesting as wheezing. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Site:** Most common site for carcinoid tumors is the **Ileum** (small intestine). * **The Rule of Metastasis:** Carcinoid syndrome usually occurs only after the tumor has metastasized to the **liver**, as the liver otherwise metabolizes the bioactive substances via the portal circulation [1]. * **Cardiac Involvement:** Right-sided heart failure (Tricuspid regurgitation/Pulmonary stenosis) is common. Left-sided lesions are rare because the lungs metabolize serotonin. * **Treatment:** **Octreotide** (Somatostatin analogue) is the drug of choice to manage symptoms.

Q: What is the most common organ involved in Multiple Endocrine Neoplasia type 1 (MEN-1)?

Parathyroid. **Explanation:** **Multiple Endocrine Neoplasia type 1 (MEN-1)**, also known as Wermer’s syndrome, is an autosomal dominant disorder caused by a mutation in the *MEN1* gene (encoding the protein Menin). It is classically characterized by the "3 Ps": **P**arathyroid, **P**ancreas, and **P**ituitary. 1. **Why Parathyroid is correct:** Primary Hyperparathyroidism (PHPT) is the **most common** and often the **earliest** clinical manifestation of MEN-1, occurring in over 95% of patients by age 40. Unlike sporadic cases, parathyroid involvement in MEN-1 typically presents as multiglandular hyperplasia rather than a single adenoma. 2. **Why other options are incorrect:** * **Thyroid:** While thyroid adenomas or goiters can occasionally be seen in MEN-1 patients, they are not a defining feature. Medullary thyroid carcinoma is a hallmark of **MEN-2**, not MEN-1. * **Adrenal:** Adrenal cortical tumors (usually non-functional) occur in about 20–40% of MEN-1 cases, making them less common than parathyroid involvement. * **Testis:** Testicular tumors are not a standard component of the MEN-1 clinical triad. **High-Yield Clinical Pearls for NEET-PG:** * **The 3 Ps of MEN-1:** Parathyroid (95%), Pancreatic Islet cells (e.g., Gastrinoma, Insulinoma - 40-70%), and Anterior Pituitary (e.g., Prolactinoma - 30-40%). * **Gastrinoma** (Zollinger-Ellison Syndrome) is the most common functional enteropancreatic neuroendocrine tumor in MEN-1. * **Screening:** If a patient presents with recurrent peptic ulcers and hypercalcemia, always suspect MEN-1. * **MEN-2A:** Medullary Thyroid CA + Pheochromocytoma + Parathyroid. * **MEN-2B:** Medullary Thyroid CA + Pheochromocytoma + Mucosal Neuromas/Marfanoid habitus.

Question 1

Which of the following conditions causes hypercalcemia with a normal or low parathyroid hormone (PTH) level?

Accepted Answer

Sarcoidosis

Answer

Parathyroid adenoma

Answer

Familial hypocalciuric hypercalcemia

Answer

Parathyroid hyperplasia

Question 2

A 45-year-old man, a known case of chronic renal failure, develops rugger jersey spine. What is the probable cause?

Accepted Answer

Secondary hyperparathyroidism

Answer

Aluminium intoxication

Answer

Osteoporosis

Answer

Osteomalacia

Question 3

When hypothyroidism is caused by pituitary dysfunction (Central hypothyroidism), what is the expected laboratory profile?

Accepted Answer

No goiter, reduced TSH, low T3, T4

Answer

Goiter present, elevated TSH, low T3, T4

Answer

No goiter, elevated TSH, low T3, T4

Answer

Goiter present, reduced TSH, low T3, T4

Question 4

Which of the following is NOT recommended as part of comprehensive medical care for patients with diabetes?

Accepted Answer

Blood insulin levels annually

Answer

HbA1c testing, 2-4 times per year

Answer

Annual nutrition education

Answer

Annual lipid profile

Question 5

Periodic paralysis is seen in the setting of hypokalemia (hypokalemic periodic paralysis). A similar type of paralysis is seen in the setting of which of the following conditions?

Accepted Answer

Thyrotoxicosis

Answer

Hypothyroidism

Answer

Hypoadrenalism

Answer

Cushing syndrome

Question 6

A female presents with swelling in the neck, palpitations, and exophthalmos. Which of the following is the most likely diagnosis?

Accepted Answer

Graves disease

Answer

Granulomatous thyroiditis

Answer

Hashimoto thyroiditis

Answer

Multinodular goitre

Question 7

Carcinoid syndrome is associated with all except?

Accepted Answer

VMA in urine

Answer

Flushing of skin

Answer

Skin lesions like pellagra

Answer

Bronchospasm

Question 8

What is the most common organ involved in Multiple Endocrine Neoplasia type 1 (MEN-1)?

Accepted Answer

Parathyroid

Answer

Thyroid

Answer

Adrenal

Answer

Testis

Question 9

What is the treatment of choice for secondary hyperaldosteronism?

Accepted Answer

Drug management

Answer

Unilateral adrenalectomy

Answer

Both

Answer

None

Question 10

A 77-year-old man with a mass in the lung develops asymptomatic hyponatremia. His JVP is 4 cm, heart sounds are normal, and the lungs are clear. The urine sodium is 64 mEq/L and osmolality 550 mOsm/kg. Which of the following is the most likely diagnosis?

Accepted Answer

Syndrome of inappropriate antidiuretic hormone (SIADH) production

Answer

Nephrotic syndrome

Answer

Renal metastases from lung cancer

Answer

Lung metastases from hypernephroma

Endocrinology — MCQs

Endocrinology — MCQs

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